Device to achieve multiple reverse flexing of continuous steel strip



Jan. 4, 1966 D. HIGGINS 3,226,965

E. DEVICE TO ACHIEVE MULTIPLE REVERSE FLEXING Filed Jan. 5, 1962 OFCONTINUOUS STEEL STRIP 2 Sheets-Sheet 1 a 3mm 02 ,EDWAED 6::

BY I My 1 m6 ATTORNEYS a; F l

Jan. 4, 1966 E D. HIGGINS 3,226,965

DEVICE TO ACHIEVE MULTIPLE REVERSE FLEXING OF CONTINUOUS STEEL STRIPFiled Jan. 5, 1962 2 Sheets-Sheet 2 So I: G, 2 47 INVENTOR EDWAED D.Hleemls ATTORNEYS United States Patent 0 3,226,965 DEVI'CE T0 AQHTEVEMULTHPLE REVERSE FLEXHNG GE CQNTTNUQUS STEEL STRIP Edward D. Higgins,Palos Heights, lll., assignor to Continental an Company, fine, New York,N.Y., a corporation of New York Filed Jan. 5, 1962, Ser. No. 164,522 1tClaims. (Cl. 72-192) This invention relates in general to new and usefulimprovernents in apparatus for use in the manufacture of sheet metal,and more particularly relates to a novel apparatus to achieve multiplereverse flexing of work hardened continuous steel strip to increase theability thereof to withstand fabrication by increasing the ductility ofsuch strip.

In the manufacture of certain types of sheet metal, particularly thinsteel strip and sheet, the necessary reduction in thickness is obtainedby heavily cold rolling the starting metal stock. The resultant striphas been severely cold worked, frequently by more than 80% reduction,and although very hard and strong, it does not have adequate ductilityfor many uses. mate product is to be tin plated steel for the making ofcans, the hard rolled steel in conventional practice must be annealedand then temper rolled to a reduction of about only 1%. This very slightreduction imparts flatness and also masks the yield point elongation ofsuch steel which otherwise would be detrimental to can making or otherfabricating processes which might be employed, and yet this minorreduction does not noticeably impair the ductility resulting from theprior anneal.

When such conventional tin plate is desired in thinner gauges, i.e.,less than .008 inch thick, a variety of difliculties are encountered.For example, when thin rolled strips are pulled through the electrolytictinning line, the applied tensile force used to pull the strip sometimesresults in expensive fracture of the strip Within the electroplatingline. In order to avoid this difliculty, the steel industry hasintroduced a new type of tin plate to provide the desired thinner gaugesof metal, which new type of plate is produced in such a manner that itis less costly, per unit area, to produce than heretofore.

The new type of tin plate is produced by additional substantial coldrolling reductions after the metal strip stock has been annealed andplated with tin. The initial cold rolling is to a somewhat thicker gaugethan normal; followed by annealing, tin plating and a subsequent coldreduction of the order of 30% to 60%, resulting in a finished gauge ofas low as 0.0944 inch, and even lower, if desired. Unfortunately, whilethe finished product has a desired thinness and also a desirable highstrength and hardness, these qualities have been obtained by an almostcomplete sacrifice of ductility and by a marked directionality ofproperties. Tensile testing of such material indicates a transverseelongation of the order of 1% or less in a 2 inch gauge length and alongitudinal elongation of from less than 1% to 3%.

An alternative new means of producing such hard and strong but brittletiuplate is to anneal cold rolled steel at a thickness appreciablygreater than that desired in the final tinplate and then cold roll 30%to 60% to the final gauge followed by electroplating and flowbrightening of the tin coating. This differs from the foregoing processonly in that the tin coating is applied after the final cold rollingrather than previous thereto. However, the properties of the steel areessentially identical for equivalent cold reductions so that theproblems of utilizing this material are the same.

When cans, which have been made from this new type of tin plate, havethe rolling direction parallel to the can axis, severe fracturing of theplate is encountered during For example, if the ulti-' Patented Jan. 4,1966 manufacture. Fracture occurs primarily during forming of the sideseam hook and during flanging of the can body. These can makingoperations are ones in which large 10- calized plastic tensile strainsare introduced into the metal in a direction transverse to the rollingdirection. When these problems are avoided by having the can bodies madewith the rolling direction of the tin plate in a circumferentialdirection, fracture of the cans has been encountered when, during roughhandling, dents were produced in the body wall below the end seam seal.Therefore, in order to exploit further this newly introduced type of tinplate for can making, some of the ductility of the metal must berestored. Thermal treatment, such as annealing after the second coldreduction, is not practical since the tin coating, which is already onthe steel, will alloy with the steel at the required steel annealingtemperatures and thereupon form an excessive amount of undesired hardand brittle tin-iron alloy.

The present invention is directed to a machine for operating on this newtype of tin plate which has been given a substantial .cold reductionafter tin plating to increase the ductility thereof, and one object ofthis invention is to provide a novel apparatus to achieve multiplereverse flexing of the work hardened continuous steel strip to increasethe ability thereof to withstand fabrication by increasing the ductilitythereof, and at the same time, resulting in only minor reductions in thestrength of the steel strip.

In the past, metal sheets to be formed into can bodies have beensubjected to a grain breaking process wherein immediately prior to theshaping of the sheets in a can making process, the sheets are passedthrough a grain breaker to assure the formation of a perfectly roundcylinder by preventing the formation of flutes in the can body cylinderas fabricated at high speeds. This grain breaker consists of severalrollers disposed in vertical relation. However, while these rollers haveproduced the desired grain breaking and curvature of the individual canbody blanks, the flexing of the sheets has been relatively light, andthere has been no accompanying increase in ductility of the sheets somechanically treated.

In the steel industry, in order to remove ripples from steel sheets, asWell as other steel shapes, it is common practice to pass the steelthrough leveling rollers. As the steel passes through the levelingrollers, it is ultimately flexed with a resultant flattening of themetal. Such roller levelers used today have only a limited number ofpairs of alternatingly spaced rollers of approximately 1 /2 to 3 inchesin diameter. However, the steel industry does not flex the steel enoughto substantially exceed the yield strength except at initially non-flatportions sinoe the objective is to simply flatten or straighten and notto change any of the physical or mechanical properties of the material.

The present invention proposes broadly to use a novel machine having aseries of interlocking rollers such as in well known roller levelers,but wherein the number of rollers are greatly increased, the diametersof the rollers are greatly decreased and all of the rollers roll alongupper and lower guides and are constrained at their ends by upper andlower chains so as to provide both an increase in the number of flexuresas compared to roller leveling, and at the same time, all the aforesaidelements combine to provide for a more severe stressing of the metalwherein during a stressing of the metal, the outer layers of the sheetor strip are stressed beyond the initial yield strength of the metal ofthe sheet or strip.

Another object of this invention is to provide a novel apparatus forreverse flexing a hardened metal strip to increase the ability thereofto withstand fabrication by increasing the ductility of the strip, theapparatus including a large number of small diameter rollers wherein thediameter of the rollers varies between /8 inch and /2 inch, and whereina strip passed over the rollers will be severely stressed a large numberof times and wherein the stressing of the strip will be reversed toincrease the ductility of the strip and at the same time increase theability of the strip to withstand fabrication.

Still another object of this invention is to provide a novel apparatusthrough which a hardened steel str1p may be fed on a continuous basis toincrease the ability thereof to withstand fabrication by increasing theductility thereof, the apparatus including two endless rollerassemblies, each roller assembly being so guided to have opposed runsthereof disposed in parallel intermeshed relation so that a hardenedsteel strip passed therebetween will be severely flexed, the rollersbeing backed up by the guides for the roller assemblies wherein thesmall diameter rollers are sutficiently supported against flexure whileseverely flexing the strip.

Another object of this invention is to provide a novel apparatus forreverse flexing a work hardened continuous steel strip, the apparatusincluding a pair of guides having opposed spaced apart guide surfaces,an endless roller assembly entrained about each guide and having rollersengaged with the guide surfaces thereof, each of the roller assembliesbeing formed of a large number of small diameter rollers with each ofthe rollers having a diameter ranging from /8 inch to /2 inch, and therollers engaging the guide surfaces so as to prevent deflection of therollers during the application of a flexing force on a steel stripdisposed between the roller assemblies, even though the rollers are of arelatively small diameter.

A further object of this invention is to provide a novel apparatus forreverse flexing work hardened continuous steel strip, the apparatusincluding a pair of guides having opposed parallel guide surfaces, anendless roller assembly entrained over each of the guide surfaces andhaving opposed runs thereof disposed in intermeshed relation, each ofthe roller assemblies being formed of a plurality of long rollers andterminal links, the rollers each rolling upon the guide surface of anassociated one of the guides, and the links having projections disposedoutwardly of and alongside the guides so as to maintain the d1- rectionof movement of the roller assemblies as the roller assemblies move alongthe elongated guide surfaces.

With the above and other objects in view that will hereinafter appear,the nature of the invention will be more clearly understood by referenceto the following detailed description, the appended claims and theseveral views illustrated in the accompanying drawings:

In the drawings:

FIGURE 1 is a schematic side elevational view of the apparatus which isthe subject of this invention and shows the general arrangement of thecomponents thereof.

FIGURE 2 is a transverse vertical sectional view taken along the line2-2 of FIGURE 1 and shows further the details of the apparatus.

FIGURE 3 is an enlarged fragmentary horizontal sectional view takenalong the line 3-3 of FIGURE 2 with a portion of the roller assembly ofthe apparatus broken away, to clearly illustrate the details of thelower roller assembly, the lower guide and certain of the lowersprockcts for driving the lower roller assembly.

FIGURE 4 is an enlarged fragmentary vertical sectional view taken alongthe line 4-4 of FIGURE 2, and shows the specific relationship of theroller assemblies with respect to the drive sprockets therefor and therelationship of the links of the roller assemblies with respect to theguides.

FIGURE 5 is an enlarged fragmentary perspective view showing thespecific details of construction of one of the roller assemblies.

In FlGURE 1 of the drawings, there is schematically illustrated theapparatus which is the subject of this invention for preparing workhardened continuous steel strip for use by the can making industry. Theapparatus, which is generally referred to by the numeral 8, hasassociated therewith a coil pay-out stand supporting a coil C of workhardened continuous steel strip S. Also associated with the apparatus 8is a recoiler 10 having supported thereby a further coil C on which thestrip S is reeled. Prior to the entry of the strip S into the apparatus8, the strip S passes between a pair of feed control rollers ill, 11.

The strip S is relatively thick when it is initially rolled as comparedto the final product. The strip S after being initially rolled, wasannealed, after which it was passed through an electroplating bath inthe customary manner so that tin coatings are applied to opposite facesthereof. The strip S, after having been coated, was then passed througha series of cold reduction rollers wherein the thickness of the strip Swas reduced to 60%. At the end of the rolling process, the strip S is inthe form of a new type of hard, cold rolled tin plate which is nowcommercially available from a number of steel mills, e.g., from the US.Steel Corporation under the designation Ferrolite.

The 30% to 60% cold rolled plate or strip, as it comes from the coldreduction rollers of the steel mill, is relatively hard and brittle, andtherefore is only suitable for limited field of usage by the canindustry. However, it has a very great economic advantage, were thebrittleness relieved by some operation. For every base box, i.e., 31,360sq. in., which is coated with tin at a gauge, for example, of 0.012inch, one obtains after cold rolling a total of two base boxes of tincoated steel 0.006 inch thick. The low cost of rolling is such thatdoubling the area of product is accomplished at a much lower cost thanwould otherwise be possible. The steel industry has recognized the lowercost per unit of this hard rolled tin plate or strip, as compared to theconventional tin plate or strip, by pricing it at per base box belowthat of conventional plate of the same gauge. Since the hard rolledplate is much stronger than conventional plate, one can use a thinnergauge of the hard roller plate with a further increment of savings ofmaterials cost amounting to 15 per box for every reduction in gauge of0.00055 inch. A potential savings to the can industry by the use of thehard rolled plate adds up to many millions of dollars. However, the fullutilization of such plate, and obtainment of related savings of metalcosts, depends on the improvement in ductility of such hard and brittleplate which may be obtained by the use of the apparatus of thisinvention.

There is another equally or perhaps more important field of applicationof this invention. The hard rolled tin plate or strip referred to thusfar has started as hot rolled steel strip which is cold rolled by to toperhaps double the final gauge, then annealed, coated with tin and againcold rolled to a final gauge. It is possible instead to cold roll hotrolled strip directly to final gauge in a five or six stand tandemrolling mill. The cold reduction of 80% to results in extremely hard andstrong steel strip which ordinarily is far too brittle to be used in theunannealed state. However, by partially restoring the ductility of suchmaterial with the practice of this invention, it could be employed formany purposes in the hard, unannealed state, either as is or with asubsequently applied tin coating or thin coating of other metal ormaterial.

The high strength of the extremely hard rolled steel makes possiblefurther reductions in gauge of metal for many fields of utilization,e.g., closures for cans. Not only are there substantial savings inamount of material, but the elimination of annealing and conventionaltemper" rolling results in appreciable savings of process cost in theproduction of this hard rolled metal strip. While an appreciable savingsin cost is expected, the exact cost savings is not yet known, because,until the present invention, there has been no way of utilizing suchvery hard and brittle plate and therefore the product has not been madenor priced commercially. Although the apparatus of this invention isprimarily intended for use in conjunction with the above described steelstrips, it may also be used in conditioning other work hardened metalsincluding aluminum, brass, copper, etc.

In accordance with this invention, either of these two types of hardrolled plate or strip or any other type of hard, brittle plate or stripmay be further worked upon as part of the continuous forming thereof inthe steel mill, or the plate or strip may be coiled subsequent to thecold reduction operation thereof and later worked upon in accordancewith the invention either at the steel mill or at the can makers plant.For purposes of convenience, the working of the hard and strong butbrittle cold rolled plate or strip S in accordance with the inventionhas been illustrated with the strip S being supplied in coil form.

The apparatus 8, for illustration purposes, is shown as including a base12 which may be of any desired construction. The base 12 has a pluralityof longitudinally spaced supports 13 extending upwardly from the sidesthereof and supporting a lower guide 14. It is to be noted that theundersurface of the lower guide 14 is spacedabove the base 12 to providethe necessary clearance for a lower roller' assembly to be described indetail hereinafter, the lower roller assembly being entrained over thelower guide 14 and being generally referred to be the 'numeral 15.

At each end of the lower guide 14 there is a horizontally disposed,transversely extending drive shaft 16. Each drive shaft 16 is supportedby a pair of bearing assemblies 17, the bearing assembly 17 being, inturn, supported by support member 18 secured to opposite sides of theguide 14 and projecting longitudinally therefrom. Each drive shaft 16carries a sprocket assembly, generally referred to by the numeral 19.

Suitable supports 20 extend upwardly from opposite sides of the base 12and are connected together at their upperends by transverse framemembers 21. The transverse frame members 21 support a hydraulic liftassembly, generally referred to by the numeral 22. The lift assembly 22is schematically illustrated as including a cylinder 23 carried by theframe members 21, and a piston 24 within the cylinder 23, the piston 24having a large piston rod 25 projecting downwardly out of the cylinder23 and secured to an upper frame member 26 by means of a support flange27'.

The upper frame member 26 serves both as a guard for an upper rollerassembly, generally referred to by the numeral 27, and as a support foran upper guide 28, the guide 28 being suspended from the frame member 26by means of supports 29. At this time, it is pointed out that the upperguide 28 is identical with the lower guide 14 and is provided with apair of drive shafts 30 mounted at opposite ends thereof. The driveshafts 30 are supported in bearing units 31 which, in turn, are carriedby longitudinally extending supports 32 secured to opposite sides of theupper guide 28. Each of the shafts 30 supports a sprocket assembly,generally referred to by the numeral 33, the sprocket assemblies 33'supporting the upper roller assembly 27 and driving the same. It is tobe understood that the upper roller assembly 27 will be formedidentically with the lower roller assembly 15.

Reference is now made to FIGURE 5 in detail, Wherein there is shown aportion of the lower roller assembly 15. The roller assembly is formedof a plurality of transverse rollers 34, each of which extends the fullwidth of the lower roller assembly 15. The rollers 34 are connectedtogether by links 35 disposed at the opposite ends of the rollers 34.The links 35 join together two adjacent rollers 34 and the links 35 aredisposed in rows with links 35 of adjacent rollers being disposed inalternating lapped relation. Each of the rollers has an integral endextension 36 of a reduced diameter and each link is provided with a pairof bearings 37 in each of which a reduced diameter extension 36 of aroller 37 is journaled. If desired, the bearings 37 may be simply in theform of accurate bores in the links 35. Also, while the ends of theextensions 36 have been illustrated as being riveted, the links 35 maybe secured to the extensions 36 by means of washers and either snap pinsor snap links, as is customary in roller chain construction. Dependingupon the requirements of the apparatus 8, the rollers 34 will havediameters ranging from inch to /2 inch. Each of the links has aprojecting guide portion 38 for engagement with the edges of guide 14 inthe case of the lower roller assembly 15.

At this time, it is again pointed out that the upper roller assembly 27is of a construction identical to the roller assembly 15 and istherefore not described in detail here.

Reference is noW made to FIGURES l and 4 of the drawings wherein it isshown that the guides 14 and 28 have opposed guide surfaces 39 and 40,respectively. The guide surface 39 has the rollers 34 engaged therewithfor the purpose of transmitting radial forces imposed upon the rollers34 to the guide surface 39. The guide surface 40 has the rollers 34 ofthe upper roller assembly 27 engaged therewith for receiving radialforces applied to the rollers of the upper assembly 27.

The guide surfaces 39, 40 have widths corresponding to the lengths ofthe rollers 34, as is best shown in FIG- URE 2. As a result, theinnermost links .35 of the sets of links disposed at opposite ends ofthe rollers 34 run alongside the edges of the guides 14, 28 and maintainthe roller assemblies 15, 17 in alignment with the guides 14, 28.

The sprocket assemblies 19 and 32 being identical, only the sprocketassembly 19 will be described in detail here. As is best shown inFIGURES 3 and 4, the sprocket assembly 19 is formed of a plurality ofsprockets 41 spaced along the drive shaft 16 with the sprockets 41 beingspaced apart by sprocket spacers 42 also carried by the shaft 16. It isto. be noted that each of the sprockets 41 is provided with notches 44of a configuration to receive the rollers 34. In this manner, thesprockets are interlocked with the roller assembly 15.

Attention is now directed to FIGURE 3, wherein it is pointed out that inaddition to the supports 18 carrying the bearings 17, the guide 14 isprovided with intermediate stub supports 45 which project in betweenadjacent sprockets 41 and overlie the shaft 16 to provide a suitableguide surface for the rollers 34 passing from the sprockets 41 onto theguide surface 39. The stub supports 45 provide the load carryingcapacity required to flex the strip S as it enters the apparatus 8 andminimize the bearing loads on the shafts 16 and 30 at the entering endof the apparatus 8 by supporting the rollers 34 so that their load isnot transmitted to the sprockets on the shafts 16 and 30. If desired,the sprocket spacers 42 could. be eliminated or modified and the stubsupports 45 provided with suitable bearing means which, when soprovided, would support the shafts 16 intermediate the spaced sprockets41 to prevent flexing of the shafts 16 due to the loads imposedthereupon. The guide 28 could be similarly formed.

The apparatus 8 also includes an electric drive motor 46 which may be ofany type and which is coupled to a longitudinally extending drive shaft47 which extends alongside one side of the base 12. The drive shaft 47is carried by suitable bearing means 48 mounted on the base 12. Thedrive shaft 47 is provided at opposite ends thereof with Worms 49 whichare meshed with worm wheels 50 on the ends of the shafts 16, as is bestshown in FIGURE 2. In this manner, the two sprocket assemblies 19 aredriven in unison.

The sprocket assemblies 33 are driven by gears 51 mounted on the shafts30 and meshed with the gears 50. However, it is to be noted that thesprocket assemblies 33 are slightly out of rotational phase with thesprocket assemblies 19 so that the opposed portions of the rollerassemblies 15and 27 are out of phase onehalf of the spacing between apair of rollers 34. in this manner, the rollers 34 of the two rollerassemblies 15 and 27 may be disposed in meshed relation so as to definea wave-like path for the strip S between the op posed runs of the rollerassemblies 15 and 27.

It is pointed out that the gears 51}, 51 are of such size so as topermit the proper intermeshing of the rollers of the roller assemblies15 and 27. When a greater or lesser intermeshing is desired, the gearst} and 51 may be replaced. There are, of course, other gear assemblieswhich could be utilized to permit adjustment of the intermeshing of thetwo roller assemblies 15 and 27. Such an example gear arrangement (notshown) would include idler gears or chain and sprocket drives ofconventional types.

Reference is directed to FIGURE 4 in particular wherein it will beapparent that the strip S must be engaged with two rollers 34, one eachof each of the roller assemblies 15 and 27, to obtain a complete flexureof the strip S as it passes between these two rollers and is flexedfirst one way on the first roller and then reverse flexed on the secondroller, each succeeding pair of rollers producing a complete flexure ofthe strip S as it passes between the'roller assemblies 15 and 27.

lit will be understood that as the strip S passes between the opposedruns of the roller assemblies 15 and 27, not only will the strip S beflexed by the initial engagement thereof by the roller assemblies 15 and27, but due to the fact that the rollers 34 will rotate through theirrolling engagement with the guide surfaces 39 and 40, the movement ofthe strip S relative to the guides 14 and 28 will be twice that of theaxes of the rollers in'roller assemblies 15 and 27, with the result thatthe strip will be fed between the roller assemblies 15 and 27 to obtainthe desired reverse flexing thereof and the flexing of the strip S willbe continuous. It is the movement of the rollers 34 relative to theguide surfaces 39 and 44 that requires twice the number of rollers toeffect the required number of complete flexures since the rollers 34move at one half the speed of the strip S relative to guide surfaces 39and 4t}, and therefore only half as many complete flexures areaccomplished in a given length of guide surface.

Any number of flexures provided by the apparatus 8 must be withinpractical limits in order to permit the apparatus 8 to be of asufliciently small size to be economically feasible. It is to beunderstood, however, that the number of rollers of the roller assemblies15 or 27 engaged with the strip S and the diameters of the rollers 34must be such as to produce more than a mere roller leveling of the stripS. As the hard, cold rolled strip S passes around the rollers of theroller assemblies 15 and 27, it must be stressed to the extent that atleast that surface layer of the strip S in tension remote from theparticular roller assembly is stressed well beyond the yield strength ofthe metal of the hard rolled strip S. Further, in the working of thehard, cold rolled tin plate or strip having severely cold worked steelsubstrate as the base thereof, the surface layer of the steel stripunder compression is also stressed Well beyond the yield strength of themetal of the strip S. Tests have indicated that the metal should bestressed beyond its yield strength to a depth of from to 40% of thethickness of the strip S .inwardly from each stressed facing layerthereof. Of course, the deeper the penetration of work within the rangespecified, the fewer are the number of cycles of reverse stress requiredto obtain the desired increase in ductility, but flexing must obviouslybe stopped prior to the initiation of any fatigue damage.

For any given number of cycles of reverse flexing, e.g., 10 or 100 or1,000, there will be a stress below the ultimate tensile strength whichwill be sufficient to cause fracture after the specified number ofcycles of stressing. For the same number of cycles of stress, there willbe a lower stress at which no visible fracture occurs but at whichmicrocracks are formed'which would ultimately cause fracture. The lineof stress to cause microcracks versus the number of cycles to form theseat each stress is called a damage curve. It is requisite, in thepractice of this invention, that the number of cycles of stressing thesurface layers beyond their yield strength by flexure should be lessthan the number of cycles to cause damage at the stress caused by thatflexure. Ductility is increased by this invention when the combinationof number of cycles of flexure and maximum flexural stress are sorelated that no fatigue damage occurs.

In test apparatus, it has been found that increase in ductility of thestrip of hard, cold rolled tin plate in going. from one to ten cycles offlexure was approximately equal to the increase of going from 10 topasses. Thus, while in general there was a continuing benefit, thebenefit corresponded to the logarithmic increases in number of passes.From a commercial standpoint, it is believed that approximately 100complete cycles of reverse flexing is the most economically feasiblenumber considering results in the way of increase in ductility of thestrip and the machinery required for obtaining an increased number ofcycles of reverse flcxure. This would require the engagement of thestrip S with on the order of 400 of the. rollers 34 as the stripv Spasses through the apparatus 8. This will require on the order of 200rollers 34 in engagement with each of the guide surfaces 39, 40 at alltimes.

The apparatus 8 is particularly adaptable to the required reverseflexing of relatively thin strip, such as the strip S, in that adequatesupport can be obtained for the very small diameter rollers so that arelatively severe flexing of the strip S can be obtained and at the sametime the apparatus 8 is relatively compact so that the desired reverseflexing can be obtained in a relatively short distance. In addition, therollers are not continuously engaged with the strip S so as to permitdissipation of heat which may be involved dueto the rolling contact ofthe rollers 34 with both the strip S and the guide surfaces 39 and 40.

From the foregoing, it will be seen that novel and advantageousprovision has been made for carrying out the desired end. However,attention is directed to the fact that variations may be made in theexample apparatus disclosed herein without departing from the spirit andscope of the invention, as defined in the appended claims.

I claim: 1

1. An apparatus to achieve multiple reverse flexing of work hardenedcontinuous metal strip to increase the ability thereof to withstandfabrication by increasing the ductility thereof, said apparatuscomprising a pair of elongated guides having opposed race surfaces, acontinuous roller assembly including a plurality of rollers entrainedabout each of said guides, drive meansengaged with said rollerassemblies for driving said roller assemblies in unison and with rollersof said roller assemblies in staggered relation, means connected to oneof said guides for moving said one guide vertically relative to theother of said guides and retaining said one guide vertically in anadjusted position relative to said other guide, each of said rollersbeing of a diameter ranging from Ms to /2 inch.

2. An apparatus to achieve multiple reverse flexing of:

work hardened continuous steel strip to increase the ability thereof towithstand fabrication by increasing the ductility thereof, saidapparatus comprising a pair of elongated guides having opposed racesurfaces, a continuous roller assembly including a plurality of rollersentrained about each of said guides, drive means engaged with saidroller assemblies for driving said roller assemblies in unison and withrollers of said roller assemblies in staggered relation, means connectedto one of said guides for moving said one guide vertically relative tothe other of said guides and retaining said one guide vertically in anadjusted position relative to said other guide, each of said rollersbeing substantially A inch in diameter.

3. An apparatus to achieve multiple reverse flexing of work hardenedcontinuous steel strip to increase the ability thereof to withstandfabrication by increasing the duetility thereof, said apparatuscomprising a pair of elongated guides having opposed race surfaces, acontinuous roller assembly including a plurality of rollers entrainedabout each of said guides, drive means engaged with said rollerassemblies for driving said roller assemblies in uni son and withrollers of said roller assemblies in staggered relation, means connectedto one of said guides for moving said one guide vertically relative tothe other of said guides and retaining said one guide vertically in anadjusted position relative to said other guide, each of said rollerassemblies being formed of a plurality of transverse rollers, linksarranged in rows at opposite ends of said rollers and connectingtogether said rollers in an endless assembly, said links being confinedby said guides against movement in a direction transverse to theelongated guides but being freely movable in a direction parallel to theelongated guides thereby maintaining alignment of said roller assemblieswith said guides, and said drive means including multiple sprocketsdisposed at opposite ends of each of said guides, each of said sprocketshaving pockets receiving said rollers.

4. An apparatus to achieve multiple reverse flexing of work hardenedcontinuous metal strip to increase the ability thereof to withstandfabrication by increasing the ductility thereof, said apparatuscomprising a pair of elongated guides having opposed race surfaces, acontinuous roller assembly including a plurality of rollers entrainedabout each of said guides, drive means engaged with said rollerassemblies for driving said roller assemblies in unison and with rollersof said roller assemblies in sta-ggered relation, means connected to oneof said guides for moving said one guide vertically relative to theother of said guides and retaining said one guide vertically in anadjusted position relative to said other guide, there being on the orderof 200 rollers engaged with each race surface.

5. An apparatus to achieve multiple reverse flexing of work hardenedcontinuous metal strip to increase the ability thereof to withstandfabrication by increasing the ductility thereof, said apparatuscomprising a pair of elongated guides having opposed race surfaces, acontinuous roller assembly including a plurality of rollers entrainedabout each of said guides, drive means engaged with said rollerassemblies for driving said roller assemblies in unison and with rollersof said roller assemblies in staggered relation, means connected to oneof said guides for moving said one guide vertically relative to theother of said guides and retaining said one guide vertically in anadjusted position relative to said other guide, there being on the orderof 200 rollers engaged with each race surface, each of said rollersbeing of a diameter ranging from A3 inch to /2 inch.

6. An apparatus to achieve multiple reverse flexing of work hardenedcontinuous metal strip to increase the ability thereof to withstandfabrication by increasing the ductility thereof, said apparatuscomprising a pair of elongatedlguides having opposed race surfaces, acontinuous roller assembly including a plurality of rollers entrainedabout each of said guides, drive means engaged with said rollerassemblies for driving said roller assemblies in unison and with rollersof said roller assemblies in staggered relation, means connected to oneof said guides for moving said one guide vertically relative to theother of said guides and retaining said one guide vertically in an adjusted position relative to said other guide, there being on the orderof 200 rollers engaged with each race surface, each of said rollersbeing substantially A inch in diameter.

7. An apparatus to achieve multiple reverse flexing of work hardenedcontinuous metal strip to increase the abil ity thereof to withstandfabrication by increasing the ductility thereof, said apparatuscomprising a pair of elongated guides having opposed race surfaces, acontinuous roller assembly including a plurality of rollers entrainedabout each of said guides, drive means engaged with said rollerassemblies for driving said roller assemblies in unison with saidrollers of said roller assemblies in staggered relation, and each ofsaid rollers being of a diameter ranging from /8 to /2 inch.

8. An apparatus to achieve multiple reverse flexing of work hardenedcontinuous metal strip to increase the ability thereof to withstandfabrication by increasing the ductility thereof, said apparatuscomprising a pair of elongated guides having opposed race surfaces, acontinuous roller assembly including a plurality of rollers entrainedabout each of said guides, drive means engaged with said rollerassemblies for driving said roller assemblies in unison and with rollersof said roller assemblies in staggered relation, and there being on theorder of two hundred rollers engaged with each race surface.

9. The apparatus as defined in claim 7 wherein said roller assembliesinclude a plurality of connecting links, and said links include guidemeans engaging associated ones of said elongated guides for guiding saidroller assemblies in the movement thereof along said race surfaces.

10. The apparatus as defined in claim 8 wherein said roller assembliesinclude a plurality of connecting links and said links include guidemeans engaging associated ones of said elongated guides for guiding saidroller assemblies in the movement thereof along said. race surfaces.

References Cited by the Examiner UNITED STATES PATENTS 2,391,419 12/1945Holtz 153102 FOREIGN PATENTS 863,335 1/1953 Germany. 834,206 5/1960Great Britain.

CHARLES W. LANHAM, Primary Examiner.

WHITMORE A. WILTZ, MICHAEL V. BRINDISI,

Examiners.

1. AN APPARATUS TO ACHIEVE MULTIPLE REVERSE FLEXING OF WORK HARDENEDCONTINUOUS METAL STRIP TO INCREASE THE ABILITY THEREOF TO WITHSTANDFABRICATION BY INCREASING THE DUCTILITY THEREOF, SAID APPARATUSCOMPRISING A PAIR OF ELONGATED GUIDES HAVING OPPOSED RACE SURFACES, ACONTINUOUS ROLLER ASSEMBLY INCLUDING A PLURALITY OR ROLLERS ENTRAINEDABOUT EACH OF SAID GUIDES, DRIVE MEANS ENGAGED WITH SAID ROLLERASSEMBLIES FOR DRIVING SAID ROLLER ASSEMBLIES IN UNISON AND WITH ROLLERSOF SAID ROLLER ASSEMBLIES IN STAGGERED RELATION, MEANS CONNECTED TO ONEOF SAID GUIDES FOR MOVING SAID ONE GUIDE VERTICALLY RELATIVE TO THEOTHER OF SAID GIDES AND RETAINING SAID ONE GUIDE VERTICALLY IN ANADJUSTED POSITION RELATIVE TO SAID OTHER GUIDE EACH OF SAID ROLLERSBEING OF A DIAMETER RANGING FROM 1/8 TO 1/2 INCH.